Fix bug in stdReader

The stdReader object was not correctly handling read string.

A new test case has been added for this
Improve lookup functionality of ElfContent

Made it easier to use ElfContent to tweak items in a file
rather than getting a copy of the whole thing

 - Added a couple of 'get' functions to the ElfContent to
   make it easier to get at individual elements

 - Symbol now inherits from its POD base class to amke it easier
   to read / write them

 - Added some missing move constructors
Absorb addExec into libRuntime

A new libRutime library, this will be used to host the code for
managing the code for dynamically adding code at runtime